The present invention relates to a method and an apparatus for mounting an electronic component on a printed circuit board.
In recent years, the electronic circuit board has become highly dense and highly functional, and the individual integrated circuit electronic components have become highly functional as well. An increasing number of output pins are mounted on the electronic circuit board and consequently, the interval between output pins is becoming narrower and narrower. Under these circumstances in particular, it is required in particular that an electronic component be mounted accurately on the electronic circuit board by rotating the component to an accurate angle before the component is mounted.
An example of a conventional electronic component mounting is described below with reference FIG. 4. The apparatus comprises a table 2 for feeding a printed circuit board 1 into the apparatus and feeding the printed circuit board 1 therefrom and holding the printed circuit board 1 thereon; a supply section 3 for supplying the electronic component 6 to the printed circuit board 1; a head portion 5 for suctioning the electronic component 6 thereto and mounting the component on the printed circuit board 1; an XY-robot 4 for positioning the head portion 5 at an arbitrary position; a recognizing camera 21 for measuring the error amount of the position of the electronic component 6 suctioned by the head portion 5; and a controller 7 for sequence-controlling the apparatus.
The operation of the apparatus constructed as above is described below with reference to FIGS. 4 and 5.
The table 2 feeds the printed circuit board 1 to the center portion of the apparatus, thus holding the printed circuit board 1 therein. The XY-robot 4 moves the head portion 5 to the supply section 3 carrying the electronic component 6. The head portion 5 moves downward, thus suctioning the electronic component 6 thereto (step #11 in FIG. 5). Then, the XY-robot 4 moves the head portion 5 to a position above the end portion of the recognizing camera 21. The recognizing camera 21 recognizes the electronic component 6 (step #12) and measures the position of the head portion 5 and that of the electronic component 6 so as to calculate the positional error amount of the electronic component 6 in the rotational direction thereof (step #13). The recognizing camera 21 and the XY-robot 4 correct the positional error of the electronic component 6 in the rotational direction thereof and in the XY-direction thereof, respectively, while the XY-robot 4 is moving the head portion 5 toward an electronic component mounting position of the printed circuit board 1 (step #14). In this manner, the electronic component 6 is mounted on the printed circuit board 1 (step #15). Thereafter, the printed circuit board 1 is fed out from the apparatus by the table 2. The controller 7 performs the sequence control of the apparatus.
According to the above-described conventional construction, the positional error amount of the electronic component 6 in XY-direction is measured with the XY-robot 4 stopping the nozzle 8 of the head portion 5 above the recognizing camera 15, and the positional error amount of the electronic component 6 in the rotational direction thereof is measured with the XY-robot 4 moving the nozzle 8. Thus, the electronic component 6 is mounted on the printed circuit board 1 without checking whether or not the erroneous position of the electronic component 6 has been corrected accurately.